/*
 * Copyright (c) 2006-2011 Christian Plattner. All rights reserved.
 * Please refer to the LICENSE.txt for licensing details.
 */
package com.trilead.ssh2.packets;

import java.io.IOException;
import java.security.SecureRandom;

import com.trilead.ssh2.PacketFormatException;
import com.trilead.ssh2.PacketTypeException;
import com.trilead.ssh2.crypto.CryptoWishList;
import com.trilead.ssh2.transport.KexParameters;

/**
 * @author Christian Plattner
 * @version $Id: PacketKexInit.java 160 2014-05-01 14:30:26Z dkocher@sudo.ch $
 */
public final class PacketKexInit {
    private final byte[] payload;

    KexParameters kp = new KexParameters();

    public PacketKexInit(CryptoWishList cwl, SecureRandom rnd) {
        kp.cookie = new byte[16];
        rnd.nextBytes(kp.cookie);

        kp.kex_algorithms = cwl.kexAlgorithms;
        kp.server_host_key_algorithms = cwl.serverHostKeyAlgorithms;
        kp.encryption_algorithms_client_to_server = cwl.c2s_enc_algos;
        kp.encryption_algorithms_server_to_client = cwl.s2c_enc_algos;
        kp.mac_algorithms_client_to_server = cwl.c2s_mac_algos;
        kp.mac_algorithms_server_to_client = cwl.s2c_mac_algos;
        kp.compression_algorithms_client_to_server = cwl.c2s_comp_algos;
        kp.compression_algorithms_server_to_client = cwl.s2c_comp_algos;
        kp.languages_client_to_server = new String[]{""};
        kp.languages_server_to_client = new String[]{""};
        kp.first_kex_packet_follows = false;
        kp.reserved_field1 = 0;

        TypesWriter tw = new TypesWriter();
        tw.writeByte(Packets.SSH_MSG_KEXINIT);
        tw.writeBytes(kp.cookie, 0, 16);
        tw.writeNameList(kp.kex_algorithms);
        tw.writeNameList(kp.server_host_key_algorithms);
        tw.writeNameList(kp.encryption_algorithms_client_to_server);
        tw.writeNameList(kp.encryption_algorithms_server_to_client);
        tw.writeNameList(kp.mac_algorithms_client_to_server);
        tw.writeNameList(kp.mac_algorithms_server_to_client);
        tw.writeNameList(kp.compression_algorithms_client_to_server);
        tw.writeNameList(kp.compression_algorithms_server_to_client);
        tw.writeNameList(kp.languages_client_to_server);
        tw.writeNameList(kp.languages_server_to_client);
        tw.writeBoolean(kp.first_kex_packet_follows);
        tw.writeUINT32(kp.reserved_field1);
        payload = tw.getBytes();
    }

    public PacketKexInit(byte payload[]) throws IOException {
        this.payload = payload;

        TypesReader tr = new TypesReader(payload);

        int packet_type = tr.readByte();

        if(packet_type != Packets.SSH_MSG_KEXINIT) {
            throw new PacketTypeException(packet_type);
        }
        kp.cookie = tr.readBytes(16);
        kp.kex_algorithms = tr.readNameList();
        kp.server_host_key_algorithms = tr.readNameList();
        kp.encryption_algorithms_client_to_server = tr.readNameList();
        kp.encryption_algorithms_server_to_client = tr.readNameList();
        kp.mac_algorithms_client_to_server = tr.readNameList();
        kp.mac_algorithms_server_to_client = tr.readNameList();
        kp.compression_algorithms_client_to_server = tr.readNameList();
        kp.compression_algorithms_server_to_client = tr.readNameList();
        kp.languages_client_to_server = tr.readNameList();
        kp.languages_server_to_client = tr.readNameList();
        kp.first_kex_packet_follows = tr.readBoolean();
        kp.reserved_field1 = tr.readUINT32();

        if(tr.remain() != 0) {
            throw new PacketFormatException(String.format("Padding in %s", Packets.getMessageName(packet_type)));
        }
    }

    public byte[] getPayload() {
        return payload;
    }

    public KexParameters getKexParameters() {
        return kp;
    }

    public String[] getCompression_algorithms_client_to_server() {
        return kp.compression_algorithms_client_to_server;
    }

    public String[] getCompression_algorithms_server_to_client() {
        return kp.compression_algorithms_server_to_client;
    }

    public byte[] getCookie() {
        return kp.cookie;
    }

    public String[] getEncryption_algorithms_client_to_server() {
        return kp.encryption_algorithms_client_to_server;
    }

    public String[] getEncryption_algorithms_server_to_client() {
        return kp.encryption_algorithms_server_to_client;
    }

    public boolean isFirst_kex_packet_follows() {
        return kp.first_kex_packet_follows;
    }

    public String[] getKex_algorithms() {
        return kp.kex_algorithms;
    }

    public String[] getLanguages_client_to_server() {
        return kp.languages_client_to_server;
    }

    public String[] getLanguages_server_to_client() {
        return kp.languages_server_to_client;
    }

    public String[] getMac_algorithms_client_to_server() {
        return kp.mac_algorithms_client_to_server;
    }

    public String[] getMac_algorithms_server_to_client() {
        return kp.mac_algorithms_server_to_client;
    }

    public int getReserved_field1() {
        return kp.reserved_field1;
    }

    public String[] getServer_host_key_algorithms() {
        return kp.server_host_key_algorithms;
    }
}
